Electrical boxes are used to mount electrical fixtures such as ceiling fans and light fixtures. The electrical boxes commonly have tabs or flanges connected to a side wall that extend into the center of the box. The tabs include holes for receiving screws for fastening the electrical fixture to the box and for supporting the electrical fixture. The electrical box also encloses the wires and the electrical connections between the power supply and the electrical fixture. Care must be taken when mounting the electrical fixture to the electrical box to prevent the mounting screws from contacting and damaging the electrical wires within the box. Examples of electrical boxes that have inwardly extending mounting tabs are disclosed in U.S. Pat. No. 5,988,421 and U.S. Pat. No. 5,883,331.
Other electrical boxes are also known that include mounting holes for mounting the electrical box to a support. The mounting holes can be provided in the bottom wall. In other electrical boxes, the side wall is formed with a block that has a hole extending completely through the block to receive the mounting screw. Examples of such electrical boxes are disclosed in U.S. Pat. No. 6,646,201; U.S. Pat. No. 6,207,898 and U.S. Pat. No. 6,335,486.
Many different types of electrical boxes are known in the art for use as ceiling boxes. Most of the prior ceiling boxes were designed either specifically for supporting ceiling fans or specifically for supporting light fixtures. The electrical boxes that are typically used for ceiling fan support are different than those used for supporting light fixtures. In particular, electrical boxes for supporting ceiling fans typically use standard 10–32 screws, while electrical boxes for light fixture support use standard 8–32 screws. Moreover, Underwriters Laboratories (UL) has a test that electrical ceiling boxes must pass in order to be used as the sole support of a ceiling fan. Typically, a conventional electrical box used for supporting a light fixture or the like can not be used for supporting a ceiling fan.
Accordingly, when an electrical box is installed in a ceiling, the installer must determine whether a ceiling fan or a light fixture will be attached to the electrical box so that the correct type of electrical box is installed. If a light fixture type electrical box is initially installed at a particular location and then subsequently it is decided that a ceiling fan should be installed at that location, the original electrical box must typically either be modified or replaced with an electrical box which is approved for ceiling fan support. Adapting existing light fixture boxes for use with ceiling fans is often quite difficult since light fixture boxes use smaller fasteners and are generally not strong enough to support fans without substantial reinforcements or special brackets.
An electrical box that is approved for ceiling fan support can also be used to support an electrical device such as a light fixture. The National Electrical Code permits lighting fixtures to be supported by electrical boxes proved for ceiling fan support but not vice-a-versa.
Adapting existing ceiling fan boxes for use with a light fixture or the like is not always easily accomplished, since fasteners for the light fixture are different from the fasteners use with ceiling fans. For example, fasteners used with light fixtures generally smaller in diameter than fasteners used with ceiling fans. Moreover, fixture support fasteners often come in various colors, finishes and lengths as well as with various decorative features which may be difficult, if not impossible to match, in a fastener which can be used with an electrical box approved for use with ceiling fans. A National Electrical Code provision (N.E.C. 370-27 (c)) has been proposed which would require that electrical boxes approved for use with ceiling fans to be installed at most locations in a building, such as in stairways, foyers and bathrooms.
Examples of prior art ceiling fan supports are disclosed in the following U.S. Pat. No. 4,391,428 to Grimes; U.S. Pat. No. 4,880,128 to Jorgensen; U.S. Pat. No. 4,892,211 to Jorgensen; U.S. Pat. No. 5,234,119 to Jorgensen et al.; and U.S. Pat. No. 5,407,088 to Jorgensen et al.
Examples of prior art electrical boxes are disclosed in the following U.S. Pat. No. 4,315,100 to Haslbeck et al.; U.S. Pat. No. 4,580,689 to Slater; U.S. Pat. No. 4,874,905 to Schnell et al.; U.S. Pat. No. 4,954,667 to Jorgensen et al.; and U.S. Pat. No. 5,135,411 to Wiley et al. These electrical boxes generally have mounting tabs that extend inwardly with screw holes that overlie the internal cavity of the box.
In view of the above noted problems, there exists a need for an electrical box approved for use with ceiling fans that can accommodate both standard light fixture fasteners as well as ceiling fan fasteners and that can receive mounting screws without interfering with the electrical box. This invention addresses this need as well as other needs and problems which will become apparent those skilled in the art from this disclosure.